United enjoyed an early advantage at the London Stadium when referee Mike Dean harshly sent off Sofiane Feghouli for a foul on Phil Jones after 15 minutes but Antonio Valencia, Jesse Lingard and Zlatan Ibrahimovic were all guilty of spurning gilt-edged chances before the break.

David de Gea, who made two fine saves in the first 45, pivotally thwarted Michail Antonio after the interval and United eventually claimed the breakthrough in the 63rd minute through Juan Mata.

"It was not a very good performance" Mourinho said. "I think it's very difficult to play football in these circumstances, with 48 hours.

"I think it's amazing for the fans around the world, nobody has football, everybody has the Premier League, I think it's amazing, and I'm more than happy to do that, but it is very hard for the players and not just hard for the team with 10, also hard for a team with 11.

"For a team with 10 it's hard because they have to run a lot and they have to run nine instead of 10, but when you have one player more you have to think very well and my players were too tired to think well, lots of wrong decisions.

"I feel immediately when you are fresh you play simple, when you are not fresh you will play complicated and my team, especially in the first-half, everything was complicated, through the middle, always one touch, always the wrong choice, trying to play always through the middle where they compact a lot of people.